Improved magnetic properties of Cr3+ doped SrFe12O19 synthesized via microwave hydrothermal route

Cr doped Sr-hexaferrites (SrCrxFe12−xO19) were prepared using microwave-hydrothermal method and sintered at 950 °C/90 min using single mode microwave furnace. With increasing Cr3+ content, the lattice parameters changed anisotropically, where ‘a’ increases and ‘c’ decreases. The average grain sizes of sintered hexaferrite are in the range of 280–660 nm. XPS spectra shows that for higher Cr3+ content i.e., x > 0.3, both Fe2+ and Fe3+ ions are present in the crystal structure. With Cr3+ doping saturation magnetization systematically decreased and coercivity increased. Magnetic hyperfine analysis using Mössbauer technique indicates that Cr3+ ions preferentially occupy 2a, 12k, and 4f1 sites.